This is the average score you would typically shoot over par. It is based on your best 10 out of your last 20 rounds. To calculate your HI, you need to know the rating and slope of the golf course you played on.

For each of your 10 best rounds, subtract the Course Rating from your adjusted Gross Score (after applying any handicap strokes). Then, multiply the difference by 113 and divide it by the Slope Rating of the course.

Take the lowest Differential out of the 10 rounds and multiply it by 0.96. If you have more than 10 differentials, take the average of the lowest 50% (rounding fractions up).

### Determine the Average Differential

Multiply the Average Differential by 0.96.

Add together all the Handicap Differentials for the 10 rounds.

### Calculate the Handicap Differential Sum

If you have 10 differentials, simply divide the Handicap Differential Sum by 10. If you have more or fewer differentials, divide the Sum by the number of differentials you have.

### Divide by the Number of Differentials:

Take the result from Step 6 and multiply it by 0.96. Round the result to one decimal place to obtain your Handicap Index.